108,718 research outputs found
The fine art of boundary sensitivity: Second-generation professionals engaging with social boundaries in the workplace
Get PDFCrul, M.R.J. [Promotor]Ghorashi, H. [Promotor]Timmerman, C. [Promotor
Functional characterisation of the novel histamine H(3) receptor agonist, VUF 5810, on the guinea-pig isolated ileum
No full textIt is known that the activation of prejunctionally-located histamine H3 receptors down-regulates the exocytotic acetylcholine release from the myenteric plexus and thus produces a negative control on the intestinal motility [1]. Most studies were performed by using the H3 receptor agonist (R) alpha-methylhistamine, which interferes also with the histamine H4 receptor, and the non-selective ligand histamine. Therefore, more selective compounds are requested for further characterisation of the different histamine receptor subtypes. We studied the effects of the immepip analog VUF 5810, a highly selective H3 receptor agonist previously characterised in SK-NM-C cells expressing the human H3 receptor protein, on the isolated guinea pig ileum. The agonistic effect was measured in terms of inhibition of electrical stimulation (0.1 Hz, 0.5 msec, 200-250 mA)-evoked muscle contractions, which are induced by endogenous acetylcholine.
The compound VUF 5810, as well as the H3/H4 agonists, immepip and (R) alpha-methylhistamine, induced a concentration-dependent reduction of the amplitude of the neurogenic response. All these agonists gave ~60% of maximum reduction of contractions, without affecting the contractile effect elicited by exogenous acetylcholine. The calculated pD2 value of VUF 5810 (8.22) was close to that of immepip (8.53) and ~10 times higher than that of MHA (7.61).
The putative H3 receptor antagonist, FUB 649, as well as the H3/H4 receptor antagonist, thioperamide, caused a rightward shift of the concentration-response curves of VUF 5810 (pA2 FUB 649: 8.55; thioperamide: 8.94), showing a sourmountable antagonism.
VUF 5810 did not cause any change in the basal tone of the preparations, even at 100 micromol, thus excluding any effect at H1 and H2 receptors.
These results suggest that VUF 5810 behaves as a full and potent agonist at prejunctional histamine receptors controlling the acetylcholine release from the myenteric plexus. The antagonistic effect of thioperamide and FUB 649 is consistent with the involvement of H3 receptors.
[1] Bertaccini et al., in: Leurs R., Timmerman H. (eds.), The histamine H3 receptor,
Elsevier Science B.V., Amsterdam, 1998, pp 59-111
Die Bildung des frühmodernen Staates. Stände und Konfessionen. Hrsg, von H. Timmerman, 1989
No full textRecenzja: Die Bildung des frühmodernen Staates. Stände und Konfessionen. Hrsg, von H. Timmerman, 198
Synthesis and In Vitro Pharmacological Evaluation of Novel Ligands for Histamine Receptors
Get PDFLeurs, R. [Promotor]Timmerman, H. [Promotor
Polytomous diagnosis of ovarian tumors as benign, borderline, primary invasive or metastatic: development and validation of standard and kernel-based risk prediction models
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Synthesis, structure activity relationships and molecular modelling of histamine H3 receptor ligands
Get PDFTimmerman, H. [Promotor]Menge, W.M.P.B. [Copromotor]Nederkoorn, P.H.J. [Copromotor
Design, synthesis and pharmacological evaluation of non-peptidergic ligands for the human CXCR3 receptor
Get PDFLeurs, R. [Promotor]Timmerman, H. [Promotor]Esch, I.J.P. [Copromotor]de Wijtmans, M. [Copromotor
'V&G-plan ontwerpfase moet worden afgeschaft'. Onderzoek naar speciale regelgeving voor veiligheid en gezondheid
No full textTNO Bouw heeft acht jaar na de invoering van de Europese richt-lijnen in Nederland op 24 bouwprojecten en bij opdrachtgevers, architecten, ingenieursbureaus en projectontwikkelaars onderzocht wat in de praktijk het effect is van de speciale regelgeving voor veiligheid en gezondheid in de ontwerpfase van het bouwproces. Uit het onlangs uitgebrachte rapport van de onderzoekers J. Timmerman en H. Lievense blijken de V&G-plannen in de ontwerpfase vaak nutteloos en zonder toegevoegde waarde. Deze kunnen in hun huidige vorm beter worden afgeschaf
Cardiotoxic potential and CNS effects of first-generation antihistamines
No full textThe recent discovery of the serious cardiotoxic potential of the second-generation antihistamines terfenadine and astemizole has prompted a re-examination of the possible adverse effects exerted by older compounds belonging to this therapeutic class of drugs. Several clinical and preclinical studies suggest that these first-generation molecules share similar pharmacodynamic properties with newer cardiotoxic histamine H1 receptor antagonists. Both first-generation antihistamines hydroxyzine (HYD) and diphenhydramine (DPH), like astemizole and terfenadine, can act as blockers of the K+ channels encoded by the human ether-á-go-go-related gene (HERG), termed KV(r), which are the molecular determinants of the rapid component of the cardiac repolarizing current IK(Vr), and are involved in the control of neuronal excitability. Experiments performed with DPH derivatives (including the anti-parkinsonian drug orphenadrine) suggest that blockade of KV(r) channels by these compounds is independent of their ability to antagonize H1 receptors. Therefore, caution should be exercised when administering first-generation antihistamines to patients at risk of developing cardiac arrhythmias, epileptic manifestations, or both
Cardiovascular effects of the novel histamine H2 receptor agonist amthamine: interaction with the adrenergic system.
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